Electric can piercer with free stripping punch



Nov. 24, 1959 c. B. ANDERSON 2,913,321

ELECTRIC CAN PIERCER WITH FREE STRIPPING PUNCH Filed'llay 15. 1959 2 Sheets-Sheet 1 c 30 I8 ,2 I5

Q. l l r I I l 12 i I L" [:37 I2 I l g I 1 II F77??? x CHARLES B. ANDERSON INVENTOR.

ATTORNEY Nov. 24, 1959 'c. B. ANDERSON 2,913,821

ELECTRIC CAN PIERCE-R WITH FREE STRIPPI-NG PUNCH Filed May 15. 1959 2 Sheets-Sheet 2 N V EN TOR.

CHARLES B. ANDERSON A TTORNE Y United States Patent ELECTRIC CAN PIERCER wrrn FREE srmrnmc PUNCH This invention relates to sheet metal piercingdevices and has" reference to a" mechanism for cutting holes in tops of" cans containing liquids;

An object of the invention is to provide greater efficiency in a solenoid actuated can piercer.

A particular object is to provide a flexibly mounted punch in such a manner that the elfective cutting area is increased during 'the piercing stroke an decreased during theretracting' stroke, therebyproviding' free stripping of 'the punch from the hole pierced. I

Anotherobject is to provide a punchfor cutting 'holes in sheet metal and'wherein'the'punchedges are designed to reduce the power heretofore required for such piercing operations.

Anotherobject isto provide a punch for piercin'gsheet metal and wherein there is ashoulder at the base-of the punch for bending the excess metal at the 'endof the cutting operation.

Another object is to provide: an electrically operated can piercer wherein the position of the can closes'the' actuatingv switch, and whereinthe switch is located so as to avoid contactwith any spewing liquids from the can.

Another object is; to; provide an electricallyoperated can piercer wherein .the canto be piercedis tilted. beneaththepunch to close the actuating switch and. wherein con'-. tactof the punch on the top: ofrthe; can opens the switch.

These and other object will become apparent from. the following. description. and the accompany drawings wherein:

, Figurerl" is avertical'sectionuand. side elevationlof acanwpiercingdevice:in accordance with the invention.

Figure 2' isa: front elevation and brokensectional viewof. the lower portion-pf Figure: 1'. and taken at a right angle with respect thereto;

Figure- 37 isanenlarged broken elevational view of apunch assembly inaccordance with theinvention. and showing the. same relative to. the top of the-can'be to pierced. t

, Figure 4 isa bottom plan view of the-punch illustrated in Figure 3.

Figure 5 is a broken perspective. view showing the upper. rim of a cancOntacting a switch actuating. rod.

Figure 6- is an enlarged broken sectional view showing one of the punches and a portion of thepunch assembly as the same appears'after piercing a can and at-the beginning of the retracting stroke.

2,913,821 Patented Nov. 24, 1959 ice Figure 12 is a view similar to- Figures 3 and '11' and showing a further modified'form of the invention.

Figure 13 is a view similar to Figures 3, l1 and 12, and showinga still further modified formv of the invention.

Figure 14 is a top plan view of a can showing the holes formed by the punch assembly illustrated in Figurev The embodiment of the invention illustrated in Fig-; ures 1 through 6 has reference to a solenoid operated can piercing device 10 including a" circular base 11, a concentric semi cylin'd'rical' frame 12 projecting upwardly therefrom and a cylindrical housing 13 mounted on top} of the latter. It isto he noted'that the upperend 14of the frame 12 is circular and hollow, and that the open lower end of the housing 13 is joined' tothe upper periphery of the circular portion bymeans'of a circularrib 15 and matching groove 16 in the housing; Within the lower end of the housing, and integral with the upper circular portion 14, there is" an opening 17 defined by spaced parallel upstanding channels 18 on which there is mounted a commercially available solenoid" 19. Generally, the solenoid 19 is comprised of a frame 20, an electric coil 21, an armature or plunger 22, a coil spring 23 therearound and a laterally projecting end plate 24 against which the spring bears for normallymaintaining the armature in its raised position.

The. punch assembly 25 of the preferred form of the invention is best illustrated inFi'gures 3', 6 and 8 and is comprised of a rigid transverse support 26 which is secured to a' U-shaped bracket-'or' adapter 27 which; in turn, is mounted in a-hollow lower extension 2'8on the lower end of the plunger 22. As shown in Figure-'8, the bracket adapter 27 is securedin place by rivets 29 in opposite sidewalls of the extension 28. The transverse support 26 has outwardly and downwardly extending pointed ends 30 which, as will become.apparent, supports a pair of punches 31'during the piercing operation. The punches 31 are secured-to the bottom of the transverse support 26 by arelatively large rivet 32 whichext'erids into and is headed in the adapter 27.

The punches 31- are of a single sheet of 1 spring" steel or the like and are substantially triangular at their outer ends. As shownin Figure 4' the converging edges are providectwith aslight convex curve: when viewed from below, and which edges are' provided with depending knife'edges 33, which arrangementincludes' a depending point 34, hereinafter referred to asa piercing 'pointi The punches 31 generally coincide with th'e lower surfaceof the transverse support 26, but the piercing points "34 ex tend outwardly beyond the pointed supportends v30,-.and theincluded angles between the punches 31.. and. their connecting portion 35 is lessthan the included angles Figure 7 is a top planaview of the can after' thepiercing between the support ends 30 and-the transverse: support 26. An optional feature is a depending shoulder 36 in each punch 31 at the base or widest portion thereof for bending excess metalinwardly atthe end. ofthe cutting operation.

Referring now to Figure 1, it will be noted that the upper inner surface of the semi-cylindrical frame12 is inwardly inclined, as at a, whereby a can 37 to be pierced may be tilted by manual pressure sov as to cause the rear upper rim ofthe can to contact and raise a depending rod 38, the lower end ofwhich rodis vertically and. s1id= ably mounted in the rear portionofthe circular upper end 14 of the frame 12. As particularly shown iniFigures 2 and 5, there is an enlargement or boss 39 to accommodate the rod 38 which extends upwardly and operates a switch 40 mounted above the upper surface. of the solenoid coil 21. There is an ofiset b in the rod 38 above the frame end 14 for limiting the downward movement of the rod. The switch 40 shown .is a microswitch having an off button 41 on its upper end and an on button 42 on its lower end. A laterally extending leaf spring 43 mounted on the armature plate 24 is positioned to contact the off button 41, whereas a lower leaf spring 44 ispositioned to contact the on button 42. The switch 40 and lower leaf spring 44 are mounted on a bracket 45 secured to the side of the solenoid frame 20, and the extending end of said spring is connected with the upper end of the rod 38.

The modified form of the punch assembly illustrated in Figure 11 includes a straight transverse support 46 on the lower end of the plunger extension 28 and has vertical bolts 47 through the ends thereof for supporting punches 48 which are of substantially the same construction as the previously described punches 31. Nuts 49 secure the punches in place and split spring washers 46a are positioned between the punches and the support 46. It is to be understood that the holes, not shown, through the punches are slightly larger than the diameters of the bolts 47, andwhich construction and arrangement provides for flexible mounting such as that previously described. It is also pointed out that the described construction and arrangement also limits the upward flexible movement of the punches 48.

The form of the invention illustrated in Figure 12 includes a transverse support 51 and otherwise the punch assembly is substantially the same as described in connection with the preferred form of the invention. However, it is to be noted that the integral connecting portion 52 between the punches 53 is slightly bowed in a direction so that the punches 53 do not normally contact the transverse support 51.

The form of the invention illustrated in Figure 13 is comprised of a straight transverse support 54, and while the punches 55 are similar to those previously described, it is to be noted that the depending or piercing ends 56 are oppositely arranged and that the punches are beneath said support. The punches 55 are normally spaced from the support and are mounted on U-shaped springs 57 and secured to the support by bolts 58. It is to be noted that the pierced holes 59 (Figure 14) are oppositely disposed with reference to the holes 60 (Figure 7) in the other described forms of the invention, that is, having corners adjacent the rim of the can 37.

The operation of all forms of the invention is substantially the same. Contact of the point of the punch defleets the flexibly mounted punch and, since the sides of punch converge toward the point, the effective cutting area of the punch is increased. When retracting the punch the opposite is true; that is, upward movement of the punch tilts the same toward its original normal position and provides free and substantially frictionless stripping. It is also pointed out that by reason of the depending knife edges, and their progressive penetration into the metal during the piercing operation, there is a cutting rather than a shearing action. Just prior to the completion of the cutting action, the depending shoulder contacts the metal between the knives and bends the same inwardly of the can. The operation of the can piercing device illustrated in Figures 1 and 2 is as follows:

The can 37 to be pierced is placed on the base 11 and pressed inwardly of the semi-cylindrical frame 12.

piercing of holes 60 in the can 37 in accordance with the foregoing description of operation of the punch assembly. The force of the plunger assembly 25 on the can 37 causes the latter to assume a vertical position and thus release the on button 42. The upper leaf spring 43 on the solenoid plate 24 then contacts the off button 41 and de-energizes the solenoid 20, after which the spring 23 raises the plunger 22 to its normal position.

The invention is not limited to the constructions herein shown and described, but may be made in various ways within the scope of the appended claims.

What is claimed is:

1. A punch assembly for piercing holes in sheet metal, said punch assembly comprising: a plunger, a punch having a downwardly directed piercing point at one side thereof, the bottom area of said punch being generally triangular and diagonally positioned relative to the sheet metal surface to be pierced, a flexible mounting on the side of said punch opposite said piercing point, means reciprocating said plunger perpendicularly relative to the sheet metal to be pierced, and means limiting the flexible movement of said punch.

2. A punch assembly for piercing holes in sheet metal as defined in claim 1 and including depending knife edges along the sides of said punch adjacent said piercing point.

3. A punch assembly for piercing holes in sheet metal as defined in claim 1 and including a depending shoulder on the lower surface of said punch and on the side thereof opposite said piercing point.

4. An electrically operated device for piercing holes in the ends of cans, said device comprising a vertical frame open along one side thereof for receiving the can to be pierced, a solenoid mounted on the upper end of said frame and having its plunger vertically disposed, a punch assembly mounted on the lower end of said plunger and normally above but adapted to contact the can to be pierced, said punch assembly comprising a punch having a downwardly directed piercing point at one side thereof, the bottom area of said punch being generally triangular and diagonally positioned to the upper surface of the can to be pierced, a flexible mounting on the side of said punch opposite said piercing point and connected with said plunger, and means selectively reciprocating said plunger.

5. An electrically operated device for piercing holes in the ends of cans as defined in claim 4, and wherein there is a projection at the upper center inner surface of said frame, a vertical rod slidably mounted inwardly adjacent said projection and adapted to contact the rim of said can, a switch above said projection, and means operatively connecting said rod with said switch.

6. An electrically operated device for piercing holes in the ends of cans, said device comprising a vertical frame open along one side thereof for receiving a can to be pierced, a solenoid mounted on the upper end of said frame and having its plunger vertically disposed, a punch mounted on the lower end of said plunger and normally above but adapted to contact the can to be pierced, said frame including a projection at the upper center inner surface thereof, a vertical rod slidably mounted inwardly adjacent said projection and adapted to contact the rim of said can, a switch above said projection, means operatively connecting said rod with said switch, and means selectively reciprocating said plunger.

No references cited. 

